Add CHECKs to prevent segfault for incorrect IMAGE_DATA layers.
Incomplete IMAGE_DATA layers cause a segmentation fault, e.g.:
layers {
name: "mnist"
type: IMAGE_DATA
top: "data"
top: "label"
image_data_param {
batch_size: 100
}
include: { phase: TRAIN }
}
or
layers {
name: "mnist"
type: IMAGE_DATA
top: "data"
top: "label"
data_param {
source: "./data/train.txt"
batch_size: 100
}
include: { phase: TRAIN }
}
Also empty image list files cause a segfault.
This is fixed by adding 3 CHECK instructions.